Pocket adding machine

ABSTRACT

A flat housing with a first row of windows for the digits of an operand and a second row of windows for the digits of a result contains a set of parallel shafts forming several decadic stages, each stage including a drive shaft with nine staggered longitudinal ribs and a juxtaposed driven shaft with a splined profile carrying an axially slidable sprocket engageable with these ribs. A slidable bar, carrying digits visible through the operand window of the respective stage, serves to align the associated sprocket with one or more of the ribs of its drive shaft whereby a full revolution of the latter advances the driven shaft by one to nine angular steps; a wheel on the driven shaft, aligned with the result window of the stage, then displays a corresponding digit therein. A rocker arm controlled by the digit-wheel position of any lower-order stage engages another sliding sprocket on the driven shaft of the next-higher stage to align it with a tooth on the drive shaft of the latter stage for registering a carry; the drive shafts are rotatable from a common transverse input shaft in overlapping relationship to allow for successive transfers of a carry through several decades in one cycle.

United States Patent 1 1 3,589,598

[72] Inventor Fenland Suif 1,432,256 10/1922 Phinney 235/74 Hams dc Seme France Primary ExaminerStephen J. Tomsky [21 1 P 873943 Attorney-Karl E Ross [22] Filed NOV. 4, 1969 [45] Patented June 29, I971 g 506m A Responsibime Limit ABSTRACT: A flat housing with a first row of windows for the 0 digits of an operand and a second row of windows for the Seinev France digits of a result contains a set of parallel shafts forming Priority 1 1968 several decadic stages, each stage including a drive shaft with France nine staggered longitudinal ribs and a juxtaposed driven shaft with a splined profile carrying an axially slidable sprocket engageable with these ribs. A slidable bar, carrying digits visible through the operand window of the respective stage, serves to [54] sgf f fg i gf align the associated sprocket with one or more of the ribs of its aims rawmg drive shaft whereby a full revolution of the latter advances the [52] US. Cl 235/74, driven shaft by one to nine angular steps; a wheel on the 235/ 134 driven shaft, aligned with the result window of the stage, then [51} Int. Cl. ..G06c 27/00, displays a corresponding digit therein. A rocker arm con- G06c 15/26, G06c l/OO trolled by the digit-wheel position of any lower-order stage en- [50] Field of Search 235/76, 74, gages another sliding sprocket on the driven shaft of the nextl09, 108, 134 higher stage to align it with a tooth on the drive shaft of the latter stage for registering a carry; the drive shafts are rotata- References Cited ble from a common transverse input shaft in overlapping rela- UNITED STATES PATENTS tionship to allow for successive transfers of a carry through 972,360 10/1910 Graber 235/74 Several decades in one cycle- POCKET ADDING MACHINE My present invention relates to a pocket adding machine or miniature calculator designed to perform additions, subtractions and multiplications.

Such miniature calculators have heretofore been of rather complex construction, owing in part to the need for providing means to transfer a carry from one denominational order (e.g. decade) to the next.

The general object of my invention, therefore, is to provide a simplified calculator of two or more denominational orders or stages which, on account of the relatively small number of its parts, can be easily operated and can be made compact enough to fit into the users pocket.

In accordance with this invention, I provide a preferably flat housing with a first and a second row of mutually aligned windows, the windows of one row being assigned to the digits of an operand while those of the second row are assigned to the digits of a result. The housing contains a coplanar array of parallel shafts, including a drive shaft and a juxtaposed driven shaft for each denominational order or stage; although in principle the device can be used with numerical systems other than the decimal system, it will be convenient to refer to these stages simply as decades. The driven shaft of each decade is of noncircular profile, preferably splined, and carries a sprocket axially slidable thereon; this sprocket is engaged by a slide which projects from the housing for selective displacement by the user and carries a set of digits that are individually alignable with the operand window of the respective decade to display a selected digit of an augend, minuend, addend, subtrahend or multiplicand. The drive shaft is provided with axially staggered formations, such as ribs, which are engageable with the sprocket in different axial positions of the latter for advancing the driven shaft by different numbers of angular steps, i.e. up to nine steps in a decadic system. The driven shaft carries a digit wheel whose digits are individually alignable with the associated result window so as to display a digit whose magnitude depends on the number of angular steps performed by the driven shaft.

According to another feature of my invention, the driven shaft of any higher-order decade (i.e. of any denominational order other than the lowest one) carries a further sprocket which can be axially shifted between a normal and a displaced position. A rocker pivotally mounted in the housing engages this further sprocketfor shifting it under the control of the driven shaft of the next-lower decade whenever this driven shaft passes through a position requiring the transfer of a carry to the next decade. A tooth on the drive shaft of this next decade then engages the shifted second sprocket to advance its driven shaft by a further angular step so as to increase (during addition) or decrease (during subtraction) the digital value read in the result window of that decade. For the correct transfer of a carry in additionand subtraction, I prefer to provide two such teeth on opposite sides ofa camming formation which restores the rocker to normal whenever the drive shaft arrives in a home position in which a zone free from sprocketengaging formations confronts the first sprocket of the driven shaft. To cam the rocker into its off-normal position the digit wheel of the next-lower stage may be provided with a suitable projection.

The input to the several stages may comprise a manually rotatable shaft transverse to all the drive and driven shafts and a plurality of transmission elements, one for each decade, carried on that input shaft with freedom of limited relative rotation. According to a preferred embodiment, these transmission elements are sectoral driving gears intermittently meshing with smaller driven gears on the respective drive shafts. Although, in principle, it would be possible to provide these drive shafts with several peripherally spaced sets of nine ribs each whereby a fraction of a drive-shaft revolution would be sufficient to step the associated driven shaft through nine digital positions, it will generally be convenient to use only one set of ribs per stage in order to minimize the diameter of the drive shaft. The sectoral gears of the transmission elements on the input shaft are then so dimensioned as to turn each drive shaft through a full 360 for each revolution of the input shaft; during a part of such revolution, however, the drive shafts are not entrained and can be indexed in their respective home positions. Advantageously, the several transmission elements are interconnected by lost-motion couplings, such as angularly spaced crenellations, whereby the rotation of the drive shafts of successive decades is progressively staggered to allow for the consecutive transfer of a carry through all the higher-order stages in a single operating cycle. I

The above and other features of my invention will be described in greater detail hereinafter with reference to the accompanying drawing in which:

FIG. 1 is a perspective view of a bodying the invention;

FIG. 2 is an elevational view, partly in section and drawn to a larger scale, of the device shown in FIG. I; and

FIGS. 3 and 4 are cross-sectional views taken on the lines III-Ill and IV-IV, respectively, on FIG. 2.

The adding machine shown in FIG. 1 comprises a flat housing 1 having a row of first windows 2 and a row of second windows 5 in one of its major sides. A depression 6 may be used for the insertion ofa name plate or the like. A group oflugs 3, respectively aligned with the windows 2 and 5, are the projecting extremities of respective sliding bars 33 (FIGS. 2 and 4) disposed within the housing, each of these bars carrying a set of digits 34 visible through the corresponding window 2 in different positions of the bar. In the specific embodiment illustrated, there are five such lugs 3 and slides 33 corresponding to as many decades; naturally, the number of such decades can be increased or reduced at will.

The numerals appearing in window 2 are the digits of an pocket adding machine em- I operand selected by the user for performing an addition, subtraction or multiplication. An input shaft 8, projecting laterally from the housing 1, carries a crank arm 7 with a beveled handle 9 retractably pivoted thereto; in the retracted position ofthat handle, members 7 and 9 lie flat against one of the minor sides of the prismatic housing 1.

To perform an addition or a subtraction, the user registers the augend or the minuend in windows 2 by selectively retracting the lugs 3 of one or more slides 33; a single revolution of shaft 8 by the crank 7 or 9 then transfers this operand to the windows 5 whereupon a second operand, i.e. an addend or a minuend, can be similarly registered in windows 2. Upon a subsequent turning of the crank in one direction (clockwise, FIG. 1) for addition or in the opposite direction (counterclockwise) for subtraction, the result appears in the windows 5. Multiplication is carried out by registering the multiplicand in window 2 and rotating the crank 7, 9 through a number of revolutions corresponding to the desired multiplier; again, the result appears in windows 5. To erase the result, the user registers in window 2 the number appearing in window 5 and then rotates the crank once in the subtractive (counterclockwise) sense, whereupon only zeros will be seen in windows 5. In the position illustrated in FIG. 1, in which all the lugs 3 are pushed in, zeros are also read in all the windows 2.

Details of the internal construction of the machine will now be described with reference to FIGS. 2-4.

Except for the lowest-order or units decade, all the stages of my improved calculator are identical and comprise each a drive shaft 10 and a splined driven shaft 11; similar shafts 10a and Ila are provided for the first decade. The drive shafts 10 and 10a are rotatably journaled in two partitions l2 and 13 rigid with the housing I; the driven shafts 11 and 11a are similarly journaled in partition 12 and in the peripheral housing wall 19, passing freely through respective cutouts in the intermediate partition 13. Dual leaf springs 14, straddling the lower extremities of the drive shafts, are fixed to the housing 1 and engage in diametrically opposite notches (not shown) of these shafts for releasably indexing same in a home position illustrated in FIG. 2.

A set of nine longitudinal ribs 15 of axially staggered length are distributed over a little more than half the periphery of each drive shaft, the longest of these ribs (FIG. 3, left) extending over virtually the full length of the shaft between partitions l2 and 13. A sprocket 20, whose axial width is not greater than the difference in length between successive ribs 15, is axially slidable on the splined profile of each shaft 1 l or 110, this sprocket having ten teeth engageable by the ribs 15 for advancing the shaft 11 and 11a by as many angular steps (here of 36 each) as there are ribs 15 operatively aligned with that sprocket. A wheel 23 rigid with each driven shaft carries ten peripherally equispaced digits 24, these being the numerals visible through windows 5. As shown in FIG. 4, the hub of sprocket 20 is bracketed by a pair of lugs 37 on the associated slide 33, which parallels the shaft 11 or 110, whereby any displacement of this slide from its retracted position aligns the sprocket 20 with one or more ribs 15 of the corresponding drive shaft or 10a. Thus, the number of ribs so aligned increases progressively with the extent of the withdrawal of the slide and corresponds to a numerical value displayed in the as signed window 2 by one of the digits 34. Each slide is independently indexable in its selected position by a pair of flanking leaf springs 36 (similar to springs 14) engaging in notches 35.

Each shaft 10 (in contradistinction to shaft 10a) terminates above partition 13 in a head 50 carrying an eccentric upward projection or lug 16 and a pair of radially projecting teeth 17 symmetrically disposed with reference to projection 16. More particularly, the projection 16 lies in an axial plane of shaft 10 which bisects the are occupied by the ribs and which coincides with the plane of all the shaft axes in the home position of shaft 10; the teeth 17 lie outside that arc and are symmetrically disposed with reference to the bisecting plane. A second sprocket 21 is limitedly axially shiftable on each shaft 11, above the first sprocket 20 thereof, between a raised normal position and a displaced position on the level of teeth 17. To displace the sprocket 21 into this alternate position, I provide a rocker arm 28 which is pivoted at 29 to the housing 1 and whose tip 30 engages in a groove 22 of the sprocket. Rocker 28 has two dogs 31 and 32 respectively carried at its upper and lower surfaces approximately midway between its fulcrum 29 and its tip 30; the upper dog 31 coacts with a camming lug 27 on the underside of the digit wheel 23 of the next-lower stage whereas the lower dog 32 coacts with the projection 16 of the drive shaft 10 of its own stage. The location oflug 27 of wheel 23 is such that the tip 30 or rocker 28 is depressed by it during a transition from digit 9 to digit 03" or vice versa, in the corresponding window 5; such transition, of course, calls for the transfer of a carry to the next-higher decade. The return swing of rocker 28 under the control of projection 16 of shaft 10 occurs when that shaft arrives at its home position. Owing to the emplacement of dogs 31 and 32 midway along the operating end of rocker arm 28, the excursion of tip 30 and therefore the shift of sprocket 21 will be about twice as large as the height of the camming formations 27 and 16. Driven shafts l1 and 11a also have keyed to them a set of gears 25, of

. ten teeth each, which coact with respective leaf springs 26 (similar to springs 14) indexing these shafts in any of their 10 digital positions.

Input shaft 8, extending transversely to the shafts 10, 10a, 11 and lla, carries a set of tubular transmission elements 40, 40a, loosely mounted thereon and a driving element 38 keyed to the shaft, the latter having crenellations 39 received without rotary play in corresponding recesses of the first element 40a associated with drive shaft 10a. Each of the higherorder transmission elements 40 is provided with crenellations 42 engageable with some angular play by confronting crenellations 41 of the preceding element. The tubular elements or sleeves 40, 40a are integral with sectoral bevel gears 43 which, as best seen in H0. 3, extend only over an arc of 180. These sectoral gears intermittently drive coacting bevel gears 18, of half their pitch radius, on the corresponding shafts l0 and 10a. Thus, every complete revolution of input shaft 8 results in a complete revolution of each drive shaft 10, 10a, the rotation of these drive shafts beginning at successive instants during the first half of a revolution of shaft 8 and terminating at successive instants during the second half of such revolution.

Upon incipient rotation of shaft 8, the shaft 10a is first entrained but does not begin to drive the sprocket 20 of shaft 11a until the shaft 10 of the next-higher stage (tens decade) has left its home position so that its projection l 6 has disengaged the rocker 28 while its first tooth 17 has moved past its point of potential engagement with sprocket 21. If, in the course of that cycle, lug 27 on the units digit wheel depresses the first rocker 28, the final phase of rotation of the first shaft 10 turns the tens digit wheel by one digital step. Meanwhile, shaft 10 of the hundreds decade has also left its home position so that the second rocker 28 can be similarly predisposed for the transfer of a carry under the control of the lug 27 of the second digit wheel when the latter is entrained either by its sprocket 20 or by its sprocket 21. In this way, under certain conditions (e.g. upon the addition of 1 to 9999"), a carry may be successively transferred from the second to the highest (here fifth) decade.

lt will be apparent that the two teeth 17 respectively intervcne during addition and during subtraction. Theangular play afforded by the lost-motion couplings 41, 42 allows these teeth to be similarly positioned on all the shafts 10; without this angular play their distance from the aforementioned bisecting plane would have to be progressively increased, with less advantageous utilization of the peripheral surface of the drive shafts.

I claim:

1. An adding machine comprising:

a housing provided with a row of first windows and a row of second windows aligned therewith, a window from each row being assigned to a respective denominational order of a numerical system;

a coplanar array of parallel shafts in said housing extending transversely to said rows, said shafts including a drive shaft and a juxtaposed driven shaft for each denominational order, said driven shaft having a noncircular profile and being provided with a first sprocket axially slidable thereon, said drive shaft being provided with axially staggered formations engageable with said first sprocket in different axial positions thereof for advancing said driven shaft by different numbers of angular steps, the driven shaft of each denominational order other than the lowest one being provided with a second sprocket axially shiftable thereon between a normal and a displaced position;

a slide for each denominational order projecting from said housing for selective displacement and provided with a set of digits individually alignable with the associated first window to register a digit of a selected operand, said slide engaging said first sprocket for axially entraining same;

a rocker in said housing individual to said second sprocket and engaging same, the driven shaft of the next-lower denominational order being provided with camming means engageable with said rocker in a terminal angular position for shifting said second sprocket into said displaced position, said drive shafts having zones free from said formations confronting the associated driven shafts in a home position, the drive shaft of each denominational order otherthan the lowest one being provided with a pair of teeth disposed on opposite sides of said zone for engagement with the shifted second sprocket of the associated driven shaft toward the end of a revolution in a respective sense of rotation;

input means coupled with the drive shafts of all denominational orders for substantially concurrently rotating same through an angle sufficient to move all said formations thereof past a position of engagement with said first sprocket whereby the driven shaft of each denominational order is rotated through a number of angular steps corresponding to the registered operand digit, said input means including a plurality of transmission elements operatively connected with said drive shafts, a driving element directly connected with one of said transmission elements, and lost-motion coupling means interlinking said transmission elements for staggering the rotation of said drive shafts;

and a digit wheel on each driven shaft provided with a set of digits individually alignable with the associated second window to register a result digit whose magnitude depends on the number of angular steps performed by said driven shaft.

2. An adding machine as defined in claim 1 wherein said camming means comprises a projection on said digit wheel.

3. An adding machine as defined in claim 1 wherein the drive shaft of each denominational order other than the lowest one is provided with a camming formation engageable with the associated rocker member in said home position for restoring said second sprocket to normal.

4. An adding machine as defined in claim 1 wherein said drive shafts are provided with index means for releasably retaining same in said home position.

5. An adding machine as defined in claim 1 wherein said drive shafts are provided with respective driven gears and said transmission elements include sectoral driving gears of larger radius intermittently meshing with said driven gears.

6. An adding machine as defined in claim 5 wherein said driving element comprises an input shaft transverse to said set of shafts, said driving and driven gears being bevel gears, said transmission elements being carried on said input shaft for independent limited relative rotary motion.

7. An adding machine as defined in claim 6 wherein said housing is flat with a pair of major surfaces parallel to the plane of said array, said windows being formed in one of said major surfaces, said input shaft projecting from a minor housing surface and being provided with handle means adjacent said minor surface. 

1. An adding machine comprising: a housing provided with a row of first windows and a row of second windows aligned therewith, a window from each row being assigned to a respective denominational order of a numerical system; a coplanar array of parallel shafts in said housing extending transversely to said rows, said shafts including a drive shaft and a juxtaposed driven shaft for each denominational order, said driven shaft having a noncircular profile and being provided with a first sprocket axially slidable thereon, said drive shaft being provided with axially staggered formations engageable with said first sprocket in different axial positions thereof for advancing said driven shaft by different numbers of angular steps, the driven shaft of each denominational order other than the lowest one being provided with a second sprocket axially shiftable thereon between a normal and a displaced position; a slide for each denominational order projecting from said housing for selective displacement and provided with a set of digits individually alignable with the associated first window to register a digit of a selected operand, said slide engaging said first sprocket for axially entraining same; a rocker in said housing individual to said second sprocket and engaging same, the driven shaft of the next-lower denominational order being provided with camming means engageable with said rocker in a terminal angular position for shifting said second sprocket into said displaced position, said drive shafts having zones free from said formations confronting the associated driven shafts in a home position, the drive shaft of each denominational order other than the lowest one being provided with a pair of teeth disposed on opposite sides of said zone for engagement with the shifted second sprocket of the associated driven shaft toward the end of a revolution in a respective sense of rotation; input means coupled with the drive shafts of all denominational orders for substantially concurrently rotating same through an angle sufficient to move all said formations thereof past a position of engagement with said first sprocket whereby the driven shaft of each denominational order is rotated through a number of angular steps corresponding to the registered operand digit, said input means including a plurality of transmission elements operatively connected with said drive shafts, a driving element directly connected with one of said transmission elements, and lost-motion coupling means interlinking said transmission elements for staggering the rotation of said drive shafts; and a digit wheel on each driven shaft provided with a set of digits individually alignable with the associated second window to register a result digit whose magnitude depends on the number of angular steps performed by said driven shaft.
 2. An adding machine as defined in claim 1 wherein said camming means comprises a projection on said digit wheel.
 3. An adding machine as defined in claim 1 wherein the drive shaft of each denominational order other than the lowest one is provided with a camming formation engageable with the associated rocker member in said home position for restoring said second sprocket to normal.
 4. An adding machine as defined in claim 1 wherein said drive shafts are provided with index means for releasably retaining same in said home position.
 5. An adding machine as defined in claim 1 wherein said drive shafts are provided with respective driven gears and said transmission elements include sectoral driving gears of larger radius intermittently meshing with said driven gears.
 6. An adding machine as defined in claim 5 wherein said driving element comprises an input shaft transverse to said set of shafts, said driving and driven gears being bevel gears, said transmission elements being carried on said input shaft for independent limited relative rotary motion.
 7. An adding machine as defined in claim 6 wherein said housing is flat with a pair of major surfaces parallel to the plane of said array, said windows being formed in one of said major surfaces, said input shaft projecting from a minor housing surface and being provided with handle means adjacent said minor surface. 